The present invention relates to the production of semiconductors in general and to the production of thin film transistors (TFT) by a plasma enhanced chemical vapor deposition (PECVD) process in particular. Such semiconductors may be employed in a variety of electronic devices such as in LCD displays, in solar cells or in organic light emitting displays (OLED's) and many more. In today's transistors, amorphous silicon (a-Si) is most commonly used as semi conducting material and it is often deposited by a PECVD process on top of an insulator (dielectric). Unfortunately however, a-Si has relatively poor electronic properties and a-Si based devices (such as TFTs) tend to show degeneration over time. It is known in the art that microcrystalline silicon (μc-Si, also “polycrystalline silicon”) has far better electronic properties and that devices made of more crystalline material exhibit better performance such as higher electron mobility (higher field effect mobility), higher on—current, and tend to degenerate less over time (have less voltage threshold shift). It is also known in the art that both a-Si and μc-Si can be deposited onto an insulator from precursor silicon containing gasses in a PECVD process. For example, Y. Park et. al. in the Journal of Applied Physics (Vol. 90, No. 1, Jul. 2001, p 217) report several efforts and methods for growing μc-Si. The problem inherent to all these known methods is that they are either too slow—and thus economically not viable—or that they lead to a poor interface between the μc-Si and the insulator with unsatisfying electronical and mechanical properties.